Buried in the Proceedings of the Royal Society of London, in a volume printed in 1904, is an entry on “The Black Wild Cat of Transcaucasia,” by C. Satunin of Tiflis:

Although the existence in Transcaucasia of a Black Wild Cat was known long ago, the animal has never been described nor scientifically named…. That it really is a Black Wild Cat I knew well, as all the specimens I have had the opportunity of examining were alike, and as it is by no means rare in its native haunt.… I have found two mounted specimens, three skins, and three skulls of this cat, I am now certain of its validity, and I name it Felis daemon.

Satunin goes on to describe a cat the size of a large domestic male, with a coat of black to dark reddish brown, scattered with long white hairs. It had a long tail, longer than that of a domestic kitty, white claws “with a mother-of-pearl lustre” and “habits unknown.”

Today, if you traveled to the area once known as Transcaucasia (the bit of land north of Turkey, between the Black and Caspian seas), you would not find the mysterious Black Wild Cat. But that’s not because it went extinct — Felis daemon never existed in the first place.

Exactly what Satunin saw isn’t clear, but the 2002 book Mysterious Creatures: A Guide to Cryptozoology gives three theories: (1) Felis daemon was a black version of the Caucasian wildcat, Felis sylvestris caucasica. (2) The black wild cat was just a black feral domestic cat. (3) Satunin’s cats were hybrids of feral domestic kitties and Caucasian wildcats, similar to the Kellas cats of Scotland.

Now, this is going to get a little confusing because the Caucasian wildcat doesn’t exist either (it’s another one of Satunin’s finds that later got eliminated). A study of kitty DNA and domestication, published in 2007 in Science, grouped the wildcat F. sylvestris into five subspecies, and the Caucasian wildcat wasn’t one of them. That area of the world is home to both the European (F. sylvestris sylvestris) and Near Eastern (F. sylvestris lybica) subspecies. But that still leaves us with three options for Satunin’s find — wildcat, feral or hybrid.

Wildcat might be a good possibility, except that black morphs have never been seen. The European wildcat looks similar to a tabby cat, with a thick gray-brown coat striped in black. It’s possible for a black coat to have popped up as a mutation, so this choice can’t be entirely dismissed, but it probably isn’t all that likely.

Feral, too, is a completely acceptable option. Feral cats are common around the world, and Satunin may have found some black ones among the museum specimens he studied. The extra long tails, however, may argue against this theory.

Most likely what Satunin found were hybrids. The domestic cat can easily breed with European wildcats. Our house kitties are descended from a different subspecies — the Near Eastern wildcat — but all these cats are closely related and look very similar. And Satunin’s description of Felis daemon matches closely with that of another known hybrid, the Kellas cat of Scotland.

Kellas cats have been described as long-legged and gracile, with black coats tipped with white. They were accused, falsely, of killing sheep. Some people even thought the cats were creatures from mythology. However, studies of cats killed and captured from 1983 to 2002 revealed that, far from being the mythical cat sith of Scottish fairyland, the Kellas cat was just a hybrid of a European wildcat and a domestic kitty.

The Scottish wildcat used to be found throughout Britain, but it’s now relegated to the Scottish Highlands, where perhaps fewer than 100 remain, according to the Scottish Wildcat Association. One scientist warned earlier this year that these cats could completely disappear within 24 months. In the past the cats were hunted as vermin and killed for their fur. Today, disease and cars kill them. But the bigger problem is probably hybridization with feral and domestic cats. Soon, scientists warn, there may only be ferals and hybrids left in Scotland. And the Scottish wildcat will join Felis daemon as the stuff of legends.